As a bellows pump used for feeding a transport fluid such as a chemical solution or a solvent in semiconductor production, chemical industries, or the like, a bellows pump has been known which is configured to supply pressurized air to one air chamber of two hermetic air chambers thereby to cause a bellows to perform expansion operation to suck a transport fluid, and supply pressurized air to the other air chamber thereby to cause the bellows to perform contraction operation to discharge the transport fluid, for example, as disclosed in PATENT LITERATURE 1.
In such a bellows pump, the air pressure of the pressurized air to be supplied to each air chamber is generally increased in order to increase the discharge flow rate of the transport fluid. However, if the air pressure is increased, when switching is made from suction of the transport fluid by expansion operation of the bellows to discharge of the transport fluid by contraction operation of the bellows, a great pressure variation (pressure rise) occurs instantaneously, so that an impact pressure called “water hammer” is generated. When the impact pressure is generated, vibration caused by the impact pressure may be transmitted to a pump, a pipe, or a device to break the pump or the like. In addition, boiling (vapor, cavitation, etc.) of a liquid may occur due to an increase in a negative pressure during suction, which may have an adverse effect on a semiconductor production process or the like.
Therefore, in the conventional bellows pump, for example, as disclosed in PATENT LITERATURE 2, a partition wall which is elastically deformable so as to increase the volume in the bellows into which the transport fluid is sucked is provided at an end portion of the bellows as a countermeasure for reducing the impact pressure. When a pressure rise occurs in the bellows, the partition wall elastically deforms thereby to absorb the pressure rise to reduce vibration of the pump or the like.